This is a second paper fish I've designed this summer, a smaller one. This time, I decided to make him look as if he's jumping through hoops, which hint at the envelope of his body. Here is a closeup of the hoops and of the vertebral column, which is designed to move flexibly left and right, nearly curling upon itself.
Here is the closeup of the head.
The fish is now opening his mouth which turning to you.
Here is the first paper fish I designed, swimming in the air
And here they are, both of them, swimming in the air: